Evolution of peroxisomal enzymes-Lost organization of uric acid degrading enzymes during animal development-

嘌呤降解的最终产物因物种而异。嘌呤降解的最终产物在人类、类人猿和新猴中为尿酸，在除灵长类动物和旧大陆猴以外的哺乳动物中为尿囊素，在某些硬骨鱼中为尿囊素酶，在鱼类和两栖动物中为尿囊素酶，在许多无脊椎动物中为氨。嘌呤降解为尿酸盐对所有动物物种都是常见的，而尿酸盐的降解在高等动物中要不完全得多。我们报道过，在海洋鱼类中，嘌呤到尿酸盐的降解酶位于细胞质中，而尿酸盐到尿素的降解酶位于过氧化物酶体中。这表明在嘌呤降解过程中，过氧化物酶在进化过程中丢失了。尿囊素酶和尿囊素酶是鱼肝脏中的两种不同的蛋白质，而这两种酶在两栖动物肝脏中是一种复合物。我们研究了在动物进化过程中，两栖动物尿囊酶-尿囊酶复合物的形成和丢失的机制。牛蛙（Rana Catesbeiana）尿囊酶cDNA全长2112个碱基对，包含1449个碱基对的开放阅读框，对应483个残基蛋白。（53296 Da）(2)。我们克隆了斑马鱼尿囊素酶的lambda gt 11 cDNA。用PCR和DNA测序仪对cDNA进行测序。（3).在咸水鱼的肝脏中，嘌呤降解的最终产物是尿素和乙醛酸盐。乙醛酸盐可以通过丙氨酸：乙醛酸氨基转移酶转化为甘氨酸，以再利用嘌呤碳。(4)。一般认为，所有的尿囊素降解酶在哺乳动物进化过程中丢失。令人惊讶的是，在哺乳动物组织中发现了解糖酶。大鼠溶脲醇酯酶的表观Km （17 mM）远高于鱼肝溶脲醇酯酶的表观Km （0.33 mM）。哺乳动物在进化过程中通过提高尿苷酸的km而失去了在体内的功能。(5)牛蛙过氧化氢酶cdna全长1636个碱基对，包含1584个碱基的开放阅读框，编码528个氨基酸。少(59871)

End products of purine degradation vary from species to species. The end product of purine degradation is urate in humans, hominoid primates and new would monkeys, allantoin by uricase in mammals other than primates and old world monkeys, allantoate by allantoinase in some teleosts, urea by allantoicase in fish and amphibians and ammonia in many invertebrates.The degradation of purines to urate is common to all animal species, while the degradation of urate is much less complete in higher animals. We have reported that in marine fish, the degrading enzymes of purines to urate are located in the cytosol, while the degrading enzymes of urate to urea are located in the peroxisomes. This shows that in purine degradation, peroxisomal enzymes have been lost during evolution. Allantoinase and allantoicase are different proteins in fish liver, whereas the two enzymes from a complex in amphibian liver. We examined the mechanism to form amphibian allantoinase-allantoicase complex and lose in hig … More her animals during animal evolution.(1).The cDNA encoding bullfrog (Rana Catesbeiana) allantoinase is 2112 base pairs in length containing a 1449-base pair open reading frame which corresponds to a 483-residue protein.(53,296 Da) (2).We did the cloning of lambda gt 11 cDNA endoding zebra fish allantoinase. The cDNA was applified with PCR and sequenced with DNA sequencer. (3).In saltwater fish liver, the end products of purine degradation are urea and glyoxylate. Glyoxylate may be converted to glycine by alanine : glyoxylate aminotransferase for the reutilization of purine carbons. (4).It is generally accepted that all of the allantoin-degrading enzymes were lost during mammalian evolution. Surprisingly, ureidoglycollate lyase has been found in a mammalian tissue. The apparent Km (17 mM) of the rat enzyme for ureidoglycollate was much higher than (0.33 mM) of fish-liver ureidoglycollate lyase. Mammals have lost the function in vivo by elevating the km for ureidoglycollate during evolution. (5).cDNA encoding bullfrog catalase is 1636 base pairs in length containing a 1584 bases of an open reading frame that encoded 528 amino acids. (59871) Less